A power control circuit usually includes a power control module. The power control module connects to a power circuit and controls the power circuit to supply power by outputting a series of voltage pulses with a certain frequency to the power circuit. However, when a voltage source or a load in the power circuit is changed suddenly, a voltage input to the power control module will receive a voltage spike. If the voltage spike input to power control module is more than an upper threshold voltage, the power control module will be turned off due to over-voltage protection and stops outputting the series of voltage pulses with the certain frequency to the power circuit, therefore causing the power circuit to stop supplying power.